Title: Exergy analysis of natural gas/diesel combustion in homogenous charge compression ignition engines (HCCI) using multi-dimensional model

Authors: Samad Jafarmadar

Addresses: Technical Education Faculty, Mechanical Engineering Department, Urmia University, Urmia, West Azerbaijan 57561-15311, Iran

Abstract: One of the major problems in application of HCCI combustion engines is lack of direct control for combustion timing. A suggested solution for combustion timing control is using a binary fuel blend in which two fuels with different auto-ignition characteristics are blended at various ratios. The aim of this research is to investigate the energy and exergy analysis of HCCI combustion when a blended fuel, which consists of diesel fuel and natural gas, is used. In order to accomplish this task, the extended coherent flame model-three zone model (ECFM-3Z) has been used, which performs combustion computations using a CFD model. For the exergy analysis, an in-house computational code is developed, which uses the results of the energy analysis and combustion modelling at various cases. With crank position at different gas fuel-air ratios, various rate and cumulative exergy components are identified and calculated separately. It is found that as gas fuel-air ratio increases from 0.3 to 0.8, the exergy efficiency decreases 46.2% to 37.9%. Furthermore, the value of irreversibility decreases from 24% to 21.4% of the mixture fuels chemical exergies.

Keywords: exergy analysis; dual fuel blends; diesel fuel; natural gas; multidimensional modelling; homogenous charge compression ignition engines; HCCI combustion engines; combustion timing; energy analysis; CFD; computational fluid dynamics; combustion modelling; irreversibility.

DOI: 10.1504/IJEX.2015.071561

International Journal of Exergy, 2015 Vol.17 No.4, pp.475 - 491

Received: 08 Mar 2014
Accepted: 28 Jul 2014
Published online: 01 Sep 2015 *

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